US5391522A - Glass-ceramic for magnetic disks and method for manufacturing the same - Google Patents

Glass-ceramic for magnetic disks and method for manufacturing the same Download PDF

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US5391522A
US5391522A US08/248,757 US24875794A US5391522A US 5391522 A US5391522 A US 5391522A US 24875794 A US24875794 A US 24875794A US 5391522 A US5391522 A US 5391522A
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glass
ceramic
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mgo
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Naoyuki Goto
Katsuhiko Yamaguchi
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Ohara Inc
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Ohara Inc
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C03C10/0009—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing silica as main constituent
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
    • C03C23/007—Other surface treatment of glass not in the form of fibres or filaments by thermal treatment
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739—Magnetic recording media substrates
    • G11B5/73911—Inorganic substrates
    • G11B5/73921—Glass or ceramic substrates
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers

Definitions

  • This invention relates to a glass-ceramic for magnetic disks having a crystal structure suitable for use as a material for a magnetic disk substrate and having improved surface characteristics after polishing and a method for manufacturing the same.
  • the magnetic disk should have not a completely smooth surface but a surface whose surface roughness (Ra) is controlled to a range from 15 ⁇ to 50 ⁇ in order to prevent adsorption between the head and the disk and damage to the head and media.
  • Ra surface roughness
  • the surface of the disk must be flat and relatively smooth.
  • the material of the magnetic disk substrate must not include anisotropic crystal or other defects and its structure must be dense, homogenious and fine.
  • the material must have sufficient mechanical strength and hardness for standing a high speed rotation and-contact with the head.
  • the material must not contain Na 2 O ingredient in principle because the Na 2 O ingredient causes dispersion of sodium ion during the film forming process with resulting deterioration in characteristics of the film.
  • the material must have chemical durability against rinsing and etching with various chemicals.
  • Aluminum alloy has been conventionally used as a material of magnetic disk substrate.
  • the aluminum alloy substrate tends to produce a substrate surface having projections or spot-like projections and depressions during the polishing process due to defects inherent in the material.
  • the aluminum alloy substrate is not sufficient in flatness and surface roughness and cannot cope with the recent requirement for high density recording necessitated by increase in the amount of information.
  • Polishing is made after chemical tempering and so the tempered layer tends to cause instability in thinning the disk substrate.
  • the substrate For improving the start/stop (CSS) characteristics, the substrate must be subjected to processings for improving its mechanical and chemical textures. This prevents mass production of the product at a competitive cost.
  • the SiO 2 -Al 2 O 3 Li 2 O system crystallized glass-ceramic described in the Japanese Patent Application Laid-open No. Sho 60-229234 contains beta-quartz solid solution or beta-spodumene solid solution and has a grain diameter of crystal ranging from about 0.1 ⁇ m to about 1.0 ⁇ m.
  • the SiO 2 -Li 2 O system glass-ceramic described in the Japanese Patent Application Laid-open No. Sho 62-72547 contains lithium disilicate and lithium metasilicate as a main crystalline phase.
  • the lithium disilicate phase has a plate-like crystal having a grain diameter of crystal in the range from about 0.3 ⁇ m to about 1.5 ⁇ m and the lithium metasilicate phase has a granular crystal having a grain diameter of crystal in the range from about 0.3 ⁇ m to about 0.5 ⁇ m.
  • These glass-ceramics require the texture processings for making the surface of the glass-ceramics rough after the polishing process for improving the start/stop (CSS) characteristics which are essential for the material of magnetic disk substrate.
  • the Japanese Patent Application Laid-open No. Hei 2-247821 proposes a glass-ceramic containing a crystal phase having a texture of sheet-like or chain-like silicate.
  • the anisotropic crystal of this glass-ceramic having an acicular or rod-shaped structure causes significant holes and pits with the result that a sufficient surface roughness cannot be obtained.
  • the crystal of this glass-ceramic contains Na 2 O ingredient, there occurs dispersion of sodium ion in the film foaming process and this adversely affects the characteristics of the film.
  • an object of the invention to provide a crystallized glass-ceramic for magnetic disks which has eliminated the disadvantages of the prior art products and has excellent surface characteristics after polishing by controlling the crystal structure and crystal grain of a crystal produced. It is also an object of the invention to provide a method for manufacturing such glass-ceramic.
  • a glass-ceramic obtained by subjecting to heat treatment a base glass containing, as an essential ingredient, a MgO ingredient in the SiO 2 -Li 2 O-P 2 O 5 system has, as a crystal phase, alpha-quartz (SiO 2 ) whose grown crystal grain (secondary grain) has a globular grain structure and has excel lent surface characteristics of a polished surface by controlling the size of the crystal grain.
  • a glass-ceramic for magnetic disks achieving the above described object of the invention is formed by subjecting to heat treatment a base glass comprising in weight percent:
  • said glass-ceramic containing lithium disilicate (Li 2 O. 2SIO 2 ) and alpha-quartz (SiO 2 ) as a main crystal phase.
  • composition of the glass-ceramic of the present invention is expressed on the basis of composition of oxides as in its base glass.
  • the above described content ranges of the respective ingredients have been selected for the reasons stated below.
  • the SiO 2 ingredient is an important ingredient which produces crystals of lithium disilicate (Li 2 O.2Si O 2 ) and alpha-quarts (SiO 2 ) as a main crystal phase by heat treating the base glass. If the amount of this ingredient is below 65%, the crystal produced in the glass-ceramic is instable and its texture tends to become too rough. If the amount of this ingredient exceeds 83%, difficulty arises in melting the base glass.
  • the Li 2 O ingredient is also an important ingredient which produces lithium disilicate (Li 2 O.2SiO 2 ) crystal as a main crystal phase by heat treating the base glass. If the amount of this ingredient is below 8%, growth of this crystal becomes difficult and melting of the base glass becomes also difficult. If the amount of this ingredient exceeds 13%, the grown crystal of the glass-ceramic becomes instable and its texture tends to become too rough and, besides, chemical durability and hardness of the glass-ceramic are deteriorated.
  • Li 2 O.2SiO 2 lithium disilicate
  • the K 2 O ingredient is an ingredient which improves melting property of the base glass and can be included up to 7%.
  • the MgO ingredient is an important ingredient which has been found in the present invention to cause a crystal grain of alpha-quartz (SiO 2 ) as the main crystal phase to grow randomly in the entire secondary grain structure. If the amount of this ingredient is below 0.5%, the above described effect cannot be obtained whereas if the amount of this ingredient exceeds 5.5%, growth of a desired Crystal becomes difficult.
  • the ZnO and PbO ingredients may also be added because they have a function similar to that of MgO. If the amount of the ZnO or PbO ingredient exceeds 5%, growth of a desired crystal becomes difficult.
  • the total amount of the MgO, ZnO and PbO ingredients should be within the range from 0.5-5.5%.
  • the P 2 O 5 ingredient is an essential ingredient as nucleating agent for the glass-ceramic. If the amount of this ingredient is below 1%, a desired crystal cannot be produced whereas if the amount of this ingredient exceeds 4%, the grown crystal of the glass-ceramic becomes instable and too rough and, besides, its stability against devitrification is deteriorated.
  • the Al 2 O 3 ingredient is an effective ingredient for improving chemical durability of the crystallized glass-ceramic. If the amount of this ingredient exceeds 7%, the melting property of the base glass is deteriorated and, as a result, the rate of crystal growth of alpha-quartz (SiO 2 ) as the main crystal phase is reduced.
  • the As 2 O 3 and/or Sb 2 O 3 ingredients may be added as refining agents in melting the base glass. It will suffice if the total amount of one or both of these ingredients-up to 2% is added to the glass.
  • one or more of B 2 O 3 , CaO, SrO, BaO, TiO 2 , SnO 2 and ZrO 2 ingredients may be added in a small amount within the range in which desired properties of the glass-ceramic according to the invention will not be impaired.
  • one or more of V 2 O 5 , MnO 2 , CuO, Cr 2 O 3 and SnO 2 ingredients up to 5% may be added.
  • lithium metasilicate Li 2 O.SiO 2
  • alpha-cristobalite SiO 2
  • the base glass having the above described composition is molten and after being subjected to heat forming or cold forming, is heat treated for crystallization under a temperature of 900° or below.
  • the glass-ceramic thus heat treated is then subjected to the lapping process and finally polishing process and the surface roughness (Ra) after final polishing comes within the range from 15 ⁇ to 50 ⁇ .
  • Table 1 shows examples (No. 1 to No. 11) of the glass-ceramic for magnetic disks according to the invention and a comparative example of the prior art SiO 2 -Li 2 O-Al 2 O 3 -P 2 O 5 system glass-ceramic together with results of measurements of the temperatures of the heat treatment, time of the heat treatment, diameter of grown crystal grain of alpha-quartz, main crystal phases and surface roughness (Ra) after polishing.
  • ⁇ -Q represents alpha-quartz (SiO 2 )
  • ⁇ -Cry represents alpha-cristobalite (SiO 2 ).
  • FIG. 1A shows the surface roughness (Ha) after polishing of the glass-ceramic of Example 4 in Table 1 and FIG. 1B that of the glass-ceramic of the comparative example in Table 1 for comparison.
  • FIG. 2A shows a scanning microscopic photograph of the crystal structure of the glass-ceramic of Example 4 and FIG. 2B that of the glass-ceramic of the comparative example for comparison.
  • the white line scales represent 1. ⁇ m.
  • materials including oxides, carbonates and nitrates are mixed and molten in a conventional melting apparatus at a temperature within the range from about 1350° C. to about 1500° C.
  • the molten glass is stirred to homogenize it and thereafter formed into a desired shape and annealed to provide a formed glass.
  • this formed glass is subjected to heat treatment to produce the crystal nucleus and is held for about one to five hours at the above described temperature of crystallization to produce the desired glass-ceramic.
  • the above described glass-ceramic is lapped for about 10 to 20 minutes with grains having average grain diameters ranging from 9 ⁇ m to 12 ⁇ m and then is finally polished for about 30 to 40 minutes with cerium oxide having average grain diameters ranging from 1 ⁇ m to 2 ⁇ m.
  • the glass-ceramic of Example No. 4 has the desired surface roughness but the glass-ceramic of the comparative example has no such desired surface roughness.
  • the crystal grains of the glass-ceramic of Example No. 4 exhibit the globular secondary grain structure and are uniformly distributed in the glass-ceramic whereas the crystal grains of the comparative example exhibit the acicular or rod-like grain structure and, accordingly, the desired surface roughness cannot be obtained.
  • the grain diameter of the glass-ceramic according to the invention the grain diameter can be controlled to the range from 0.3 ⁇ m to 3 ⁇ m by heat treatment.
  • the glass-ceramic for magnetic disks according to the invention is obtained by heat treating a SiO 2 -LiO 2 -P 2 O 5 -MgO system glass of a specific composition range and, therefore, the main crystal phase thereof consists of lithium disilicate (Li 2 O.2SiO 2 ) and alpha-quartz (SiO 2 ).
  • the grown crystal grain (secondary grain) of alpha-quartz has a globular grain structure which enables control of the grain size by heat treatment and achievement of a desired surface roughness of the polished surface whereby the glass-ceramic according to the invention can be utilized as an excellent magnetic disk substrate.
  • the glass-ceramic according to the invention comprising the steps of melting and forming the above described base glass and then subjecting the formed glass to heat treatment and crystallizing processing, the glass-ceramic which has excellent characteristics can be manufactured at good yield.

Abstract

A glass-ceramic for a magnetic disk substrate in which the grain size can be controlled and the surface roughness after polishing is within the range from 15 Å to 50 Å is provided by heat treating a base glass including in weight percent:
______________________________________
SiO2 65-83% Li2 O 8-13% K2 O 0-7% Mgo + ZnO + PbO 0.5-5.5% in which MgO 0.5-5.5% ZnO 0-5% PbO 0-5% P2 O5 1-4% Al2 O3 0-7% As2 O3 + Sb2 O3 0-2% ______________________________________
The glass-ceramic contains lithium disilicate (Li2 O. 2SiO2) and alpha-quartz (SiO2) as the main crystal phases.

Description

This application is a continuation of U.S. patent application Ser. No. 08/092,551 filed Jul. 16, 1993, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a glass-ceramic for magnetic disks having a crystal structure suitable for use as a material for a magnetic disk substrate and having improved surface characteristics after polishing and a method for manufacturing the same.
There has been a rapid progress in developments in magnetic diks demand for which has recently increased remarkably as external media of large scale computers and personal computers. Characteristics required generally for a magnetic disk substrate are as follows:
(1) In start/stop (CSS) characteristics of a magnetic disk, the magnetic disk should have not a completely smooth surface but a surface whose surface roughness (Ra) is controlled to a range from 15 Å to 50 Å in order to prevent adsorption between the head and the disk and damage to the head and media.
(2) Since the amount of lifting of the head tends to decrease to the order of 0.1 μm to 0.05 μm owing to improvement of recording density of the magnetic disk, the surface of the disk must be flat and relatively smooth.
(3) The material of the magnetic disk substrate must not include anisotropic crystal or other defects and its structure must be dense, homogenious and fine.
(4) The material must have sufficient mechanical strength and hardness for standing a high speed rotation and-contact with the head.
(5) The material must not contain Na2 O ingredient in principle because the Na2 O ingredient causes dispersion of sodium ion during the film forming process with resulting deterioration in characteristics of the film.
(6) The material must have chemical durability against rinsing and etching with various chemicals.
Aluminum alloy has been conventionally used as a material of magnetic disk substrate. The aluminum alloy substrate, however, tends to produce a substrate surface having projections or spot-like projections and depressions during the polishing process due to defects inherent in the material. As a result, the aluminum alloy substrate is not sufficient in flatness and surface roughness and cannot cope with the recent requirement for high density recording necessitated by increase in the amount of information.
As a material for overcoming this problem of the aluminum alloy substrate, known in the art is a glass substrate for magnetic disks made of chemically tempered glass. This glass substrate, however, has the following disadvantages:
(1) Polishing is made after chemical tempering and so the tempered layer tends to cause instability in thinning the disk substrate.
(2) For improving the start/stop (CSS) characteristics, the substrate must be subjected to processings for improving its mechanical and chemical textures. This prevents mass production of the product at a competitive cost.
(3) Since the Na2 O ingredient is included as an essential ingredient in the glass, the film forming characteristic of the glass is deteriorated with the result that a surface coating processing becomes necessary. It has recently been put into practice in the field of chemically tempered glass and crystallized glass-ceramic to make the surface of the glass rough during the polishing process for overcoming the problem of the texture processing for improving the start/stop (CSS) characteristics. This technique however is not sufficient either for realizing a stable mass production of the product at a competitive cost.
Aside from the aluminum alloy substrate and chemically tempered glass substrate, known also in the art are glass-ceramics which satisfy some of the above described requirements. For example, the SiO2 -Al2 O3 Li2 O system crystallized glass-ceramic described in the Japanese Patent Application Laid-open No. Sho 60-229234 contains beta-quartz solid solution or beta-spodumene solid solution and has a grain diameter of crystal ranging from about 0.1 μm to about 1.0 μm. For another example, the SiO2 -Li2 O system glass-ceramic described in the Japanese Patent Application Laid-open No. Sho 62-72547 contains lithium disilicate and lithium metasilicate as a main crystalline phase. The lithium disilicate phase has a plate-like crystal having a grain diameter of crystal in the range from about 0.3 μm to about 1.5 μm and the lithium metasilicate phase has a granular crystal having a grain diameter of crystal in the range from about 0.3 μm to about 0.5 μm. These glass-ceramics, however, require the texture processings for making the surface of the glass-ceramics rough after the polishing process for improving the start/stop (CSS) characteristics which are essential for the material of magnetic disk substrate.
For overcoming these problems, the Japanese Patent Application Laid-open No. Hei 2-247821 proposes a glass-ceramic containing a crystal phase having a texture of sheet-like or chain-like silicate. The anisotropic crystal of this glass-ceramic having an acicular or rod-shaped structure causes significant holes and pits with the result that a sufficient surface roughness cannot be obtained. Further, since the crystal of this glass-ceramic contains Na2 O ingredient, there occurs dispersion of sodium ion in the film foaming process and this adversely affects the characteristics of the film.
It is, therefore, an object of the invention to provide a crystallized glass-ceramic for magnetic disks which has eliminated the disadvantages of the prior art products and has excellent surface characteristics after polishing by controlling the crystal structure and crystal grain of a crystal produced. It is also an object of the invention to provide a method for manufacturing such glass-ceramic.
SUMMARY OF THE INVENTION
Accumulated studies and experiments made by the inventors of the present invention for achieving the above described object of the invention have resulted in the finding, which has led to the present invention, that a glass-ceramic obtained by subjecting to heat treatment a base glass containing, as an essential ingredient, a MgO ingredient in the SiO2 -Li2 O-P2 O5 system has, as a crystal phase, alpha-quartz (SiO2) whose grown crystal grain (secondary grain) has a globular grain structure and has excel lent surface characteristics of a polished surface by controlling the size of the crystal grain.
A glass-ceramic for magnetic disks achieving the above described object of the invention is formed by subjecting to heat treatment a base glass comprising in weight percent:
______________________________________                                    
SiO.sub.2         65-83%                                                  
Li.sub.2 O         8-13%                                                  
K.sub.2 O         0-7%                                                    
Mgo + ZnO + PbO   0.5-5.5%                                                
in which                                                                  
MgO               0.5-5.5%                                                
ZnO               0-5%                                                    
PbO               0-5%                                                    
P.sub.2 O.sub.5   1-4%                                                    
Al.sub.2 O.sub.3  0-7%                                                    
As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3                                       
                  0-2%                                                    
______________________________________
said glass-ceramic containing lithium disilicate (Li2 O. 2SIO2) and alpha-quartz (SiO2) as a main crystal phase.
DETAILED DESCRIPTION OF THE INVENTION
The composition of the glass-ceramic of the present invention is expressed on the basis of composition of oxides as in its base glass. The above described content ranges of the respective ingredients have been selected for the reasons stated below.
The SiO2 ingredient is an important ingredient which produces crystals of lithium disilicate (Li2 O.2Si O2) and alpha-quarts (SiO2) as a main crystal phase by heat treating the base glass. If the amount of this ingredient is below 65%, the crystal produced in the glass-ceramic is instable and its texture tends to become too rough. If the amount of this ingredient exceeds 83%, difficulty arises in melting the base glass.
The Li2 O ingredient is also an important ingredient which produces lithium disilicate (Li2 O.2SiO2) crystal as a main crystal phase by heat treating the base glass. If the amount of this ingredient is below 8%, growth of this crystal becomes difficult and melting of the base glass becomes also difficult. If the amount of this ingredient exceeds 13%, the grown crystal of the glass-ceramic becomes instable and its texture tends to become too rough and, besides, chemical durability and hardness of the glass-ceramic are deteriorated.
The K2 O ingredient is an ingredient which improves melting property of the base glass and can be included up to 7%.
The MgO ingredient is an important ingredient which has been found in the present invention to cause a crystal grain of alpha-quartz (SiO2) as the main crystal phase to grow randomly in the entire secondary grain structure. If the amount of this ingredient is below 0.5%, the above described effect cannot be obtained whereas if the amount of this ingredient exceeds 5.5%, growth of a desired Crystal becomes difficult.
The ZnO and PbO ingredients may also be added because they have a function similar to that of MgO. If the amount of the ZnO or PbO ingredient exceeds 5%, growth of a desired crystal becomes difficult.
For the same reason, the total amount of the MgO, ZnO and PbO ingredients should be within the range from 0.5-5.5%.
The P2 O5 ingredient is an essential ingredient as nucleating agent for the glass-ceramic. If the amount of this ingredient is below 1%, a desired crystal cannot be produced whereas if the amount of this ingredient exceeds 4%, the grown crystal of the glass-ceramic becomes instable and too rough and, besides, its stability against devitrification is deteriorated.
The Al2 O3 ingredient is an effective ingredient for improving chemical durability of the crystallized glass-ceramic. If the amount of this ingredient exceeds 7%, the melting property of the base glass is deteriorated and, as a result, the rate of crystal growth of alpha-quartz (SiO2) as the main crystal phase is reduced.
The As2 O3 and/or Sb2 O3 ingredients may be added as refining agents in melting the base glass. It will suffice if the total amount of one or both of these ingredients-up to 2% is added to the glass.
In addition to the above described ingredients, one or more of B2 O3, CaO, SrO, BaO, TiO2, SnO2 and ZrO2 ingredients may be added in a small amount within the range in which desired properties of the glass-ceramic according to the invention will not be impaired. For improving electric conductivity, one or more of V2 O5, MnO2, CuO, Cr2 O3 and SnO2 ingredients up to 5% may be added.
As other crystals than the above described crystals which constitute the main crystal phase, lithium metasilicate (Li2 O.SiO2) and alpha-cristobalite (SiO2) can be grown.
According to the method for manufacturing the glass-ceramic according to the invention, the base glass having the above described composition is molten and after being subjected to heat forming or cold forming, is heat treated for crystallization under a temperature of 900° or below. The glass-ceramic thus heat treated is then subjected to the lapping process and finally polishing process and the surface roughness (Ra) after final polishing comes within the range from 15 Å to 50 Å.
EXAMPLES
Preferred examples of the glass-ceramic according to the invention will now be described. Table 1 shows examples (No. 1 to No. 11) of the glass-ceramic for magnetic disks according to the invention and a comparative example of the prior art SiO2 -Li2 O-Al2 O3 -P2 O5 system glass-ceramic together with results of measurements of the temperatures of the heat treatment, time of the heat treatment, diameter of grown crystal grain of alpha-quartz, main crystal phases and surface roughness (Ra) after polishing. In the Table, α-Q represents alpha-quartz (SiO2) and α-Cry represents alpha-cristobalite (SiO2).
                                  TABLE 1                                 
__________________________________________________________________________
(weight %)                                                                
__________________________________________________________________________
          Examples                                                        
No.       1     2     3     4     5     6     7                           
__________________________________________________________________________
SiO.sub.2 67.5  69.0  69.5  73.0  74.0  75.5  76.0                        
Li.sub.2 O                                                                
          10.0  9.0   9.0   8.0   12.5  10.0  10.5                        
Al.sub.2 O.sub.3                                                          
          6.0   5.0   5.5   5.0   4.5   4.5   4.0                         
MgO       2.5   3.5   1.0   4.0   2.0   1.0   2.5                         
ZnO       1.0   0.5   0.5   0.5               0.5                         
PbO       1.5   1.5   4.0         2.0   2.0                               
K.sub.2 O 6.0   7.0   6.0   4.0         4.5   4.0                         
P.sub.2 O.sub.5                                                           
          2.0   1.5   2.0   4.0   2.5   2.0   2.0                         
As.sub.2 O.sub.3                                                          
          0.5   0.5         0.5   0.5   0.5   0.5                         
Sb.sub.2 O.sub.3      0.5                                                 
Others    Cao 1.0                                                         
                BaO 1.5                                                   
                      TiO.sub.2 2.0                                       
                            SrO 1.0                                       
                                  SnO.sub.2 2.0                           
          B.sub.2 O.sub.3 2.0                                             
                ZrO.sub.2 1.0                                             
Temperature of                                                            
          750   760   770   780   780   750   780                         
crystllization (°C.)                                               
Time of crystal-                                                          
          2     3     2     3     3     2     2                           
lization (Hr)                                                             
Crystal phase                                                             
          Li.sub.2 O.2SiO.sub.2                                           
                Li.sub.2 O.2SiO.sub. 2                                    
                      Li.sub.2 O.2SiO.sub.2                               
                            Li.sub.2 O.2SiO.sub.2                         
                                  Li.sub.2 O.2SiO.sub.2                   
                                        Li.sub.2 O.2SiO.sub.2             
                                              Li.sub.2 O.2SiO.sub.2       
          α - Q                                                     
                α - Q                                               
                      α - Q                                         
                            α - Q                                   
                                  α - Q                             
                                        α - Q                       
                                              α - Q                 
α - Q                                                               
          0.7   0.6   0.9   1.3   1.5   0.8   1.2                         
diameter of second-                                                       
ary grain (μ)                                                          
Surface roughness                                                         
          16    15    18    35    42    18    30                          
(Å) Ra                                                                
__________________________________________________________________________
                     Examples                Comparative                  
           No.       8     9     10    11    Example                      
__________________________________________________________________________
           SiO.sub.2 76.5  78.5  82.3  82.0  71.0                         
           Li.sub.2 O                                                     
                     10.5  9.0   12.0  11.0  12.0                         
           Al.sub.2 O.sub.3                                               
                     3.5   2.0         1.3   9.6                          
           MgO       1.0   2.5   1.0   1.0                                
           ZnO       2.0   1.0                                            
           PbO             1.0               0.9                          
           K.sub.2 O 4.0   4.0   2.5   2.5                                
           P.sub.2 O.sub.5                                                
                     2.0   1.5   1.7   1.7   1.9                          
           As.sub.2 O.sub.3                                               
                     0.5   0.5   0.5   0.5                                
           Sb.sub.2 O.sub.3                                               
           Others                            Na.sub.2 O 3.8               
                                             CaO 0.4                      
                                             SrO 0.4                      
           Temperature of                                                 
                     780   780   810   840   840                          
           crystllization (°C.)                                    
           Time of crystal-                                               
                     5     2     2     2     2                            
           lization (Hr)                                                  
           Crystal phase                                                  
                     Li.sub.2 O.2SiO.sub.2                                
                           Li.sub.2 O.2SiO.sub.2                          
                                 Li.sub.2 O.2SiO.sub.2                    
                                       Li.sub.2 O.2SiO.sub.2              
                                             Li.sub.2 O.2SiO.sub.2        
                     α - Q                                          
                           α - Q                                    
                                 α - Q                              
                                       α - Q                        
                                             α - cry                
           α - Q                                                    
                     1.5   1.4   1.0   1.3   0.2                          
           diameter of second-                                            
           ary grain (μ)                                               
           Surface roughness                                              
                     40    36    20    33    10                           
           (Å) Ra                                                     
__________________________________________________________________________
In the accompanying drawings, FIG. 1A shows the surface roughness (Ha) after polishing of the glass-ceramic of Example 4 in Table 1 and FIG. 1B that of the glass-ceramic of the comparative example in Table 1 for comparison. FIG. 2A shows a scanning microscopic photograph of the crystal structure of the glass-ceramic of Example 4 and FIG. 2B that of the glass-ceramic of the comparative example for comparison. In the photographs of FIGS. 2A and 2B, the white line scales represent 1. μm.
For manufacturing the glass-ceramics of the above described examples, materials including oxides, carbonates and nitrates are mixed and molten in a conventional melting apparatus at a temperature within the range from about 1350° C. to about 1500° C. The molten glass is stirred to homogenize it and thereafter formed into a desired shape and annealed to provide a formed glass. Then, this formed glass is subjected to heat treatment to produce the crystal nucleus and is held for about one to five hours at the above described temperature of crystallization to produce the desired glass-ceramic. In making a specimen for measuring the surface roughness (Ra), the above described glass-ceramic is lapped for about 10 to 20 minutes with grains having average grain diameters ranging from 9 μm to 12 μm and then is finally polished for about 30 to 40 minutes with cerium oxide having average grain diameters ranging from 1 μm to 2 μm.
As shown in Table 1, the glass-ceramic of Example No. 4 has the desired surface roughness but the glass-ceramic of the comparative example has no such desired surface roughness. As will be apparent from the microscopic photographs of FIGS. 2A and 2B, the crystal grains of the glass-ceramic of Example No. 4 exhibit the globular secondary grain structure and are uniformly distributed in the glass-ceramic whereas the crystal grains of the comparative example exhibit the acicular or rod-like grain structure and, accordingly, the desired surface roughness cannot be obtained. As to the grain diameter of the glass-ceramic according to the invention, the grain diameter can be controlled to the range from 0.3 μm to 3 μm by heat treatment.
In summing up, the glass-ceramic for magnetic disks according to the invention is obtained by heat treating a SiO2 -LiO2 -P2 O5 -MgO system glass of a specific composition range and, therefore, the main crystal phase thereof consists of lithium disilicate (Li2 O.2SiO2) and alpha-quartz (SiO2). The grown crystal grain (secondary grain) of alpha-quartz has a globular grain structure which enables control of the grain size by heat treatment and achievement of a desired surface roughness of the polished surface whereby the glass-ceramic according to the invention can be utilized as an excellent magnetic disk substrate.
According to the method for manufacturing the glass-ceramic according to the invention comprising the steps of melting and forming the above described base glass and then subjecting the formed glass to heat treatment and crystallizing processing, the glass-ceramic which has excellent characteristics can be manufactured at good yield.

Claims (14)

What is claimed is:
1. A glass-ceramic for magnetic disks formed by subjecting to heat treatment a base glass which consists essentially of in weight percent:
______________________________________                                    
SiO.sub.2         65-83%                                                  
Li.sub.2 O         8-13%                                                  
K.sub.2 O         0-7%                                                    
MgO + ZnO + PbO   0.5-5.5%                                                
in which                                                                  
MgO               0.5-5.5%                                                
ZnO               0.5-5%                                                  
PbO               0-5%                                                    
P.sub.2 O.sub.5   1-4%                                                    
Al.sub.2 O.sub.3  0-7%                                                    
As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3                                       
                  0-2%                                                    
______________________________________
said glass-ceramic containing lithium disilicate (Li2 O. 2SiO2) and alpha-quartz (SiO2) as the main crystal phases.
2. A glass-ceramic as defined in claim 1 wherein a grown crystal grain (secondary grain) of alpha-quartz has a globular grain structure.
3. A glass-ceramic as defined in claim 2 wherein the size of the crystal grain is controlled to the range from 0.3 μm to 3 μm by heat treatment and surface roughness (Ra) of the ground surface is in the range from 15Å to 50Å.
4. A glass-ceramic for magnetic disks as defined in claim 1 wherein the Li2 O is 9%.
5. A glass-ceramic for magnetic disks as defined in claim 1 wherein the Li2 O is 10%.
6. A glass-ceramic for magnetic disks as defined in claim 1 wherein the Li2 O is 11%.
7. A glass-ceramic for magnetic disks as defined in claim 1 wherein the Li2 O is 8%.
8. A glass-ceramic for magnetic disks as defined in claim 1 wherein the Li2 O is 10.5%.
9. A glass-ceramic for magnetic disks as defined in claim 1 wherein the K2 O is 0%.
10. A glass ceramic as defined in claim 1 wherein the glass ceramic is of the formula:
______________________________________                                    
SiO.sub.2               73.0%                                             
Li.sub.2 O               8%                                               
K.sub.2 O                4%                                               
MgO + ZnO + PbO          4.5%                                             
in which MgO             4.0%                                             
ZnO                      0.5%                                             
PbO                      0%                                               
P.sub.2 O.sub.5          4%                                               
Al.sub.2 O.sub.3         5%                                               
As.sub.2 O.sub.3         0.5%                                             
SrO                      1.0%.                                            
______________________________________
11. A glass ceramic as defined in claim 1 wherein the glass ceramic is of the formula:
______________________________________                                    
SiO.sub.2               76.0%                                             
Li.sub.2 O              10.5%                                             
K.sub.2 O                4%                                               
MgO + ZnO + PbO          3%                                               
in which MgO             2.5%                                             
ZnO                      0.5%                                             
PbO                      0%                                               
P.sub.2 O.sub.5          2%                                               
Al.sub.2 O.sub.3         4%                                               
As.sub.2 O.sub.3         0.5%.                                            
______________________________________
12. A glass ceramic as defined in claim 1 wherein the glass ceramic is of the formula:
______________________________________                                    
SiO.sub.2               76.5%                                             
Li.sub.2 O              10.5%                                             
K.sub.2 O                4%                                               
MgO + ZnO + PbO          3%                                               
in which MgO             1.0%                                             
ZnO                      2.0%                                             
PbO                      0%                                               
P.sub.2 O.sub.5          2%                                               
Al.sub.2 O.sub.3         3.5%                                             
As.sub.2 O.sub.3         0.5%.                                            
______________________________________
13. A glass-ceramic for magnetic disks formed by subjecting to heat treatment a base glass which consists essentially of in weight percent of:
______________________________________                                    
SiO.sub.2         65-83%                                                  
Li.sub.2 O         8-13%                                                  
K.sub.2 O         0-7%                                                    
MgO + ZnO + PbO   0.5-5.5%                                                
in which                                                                  
MgO               0.5-5.5%                                                
ZnO               0.5-5%                                                  
PbO               0-5%                                                    
P.sub.2 O.sub.5   1-4%                                                    
Al.sub.2 O.sub.3  0-7%                                                    
As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3                                       
                  0-2%                                                    
______________________________________
said glass-ceramic containing lithium disilicate (Li2 O. 2SIO2) and alpha-quartz (SiO2) as the main crystal phases said glass ceramic having been subjected to a lapping and polishing process which produces a surface roughness from 15 Å to 50 Å.
14. A glass-ceramic for magnetic disks as defined in claim 13 wherein the PbO is 1 to 4%.
US08/248,757 1993-05-19 1994-05-25 Glass-ceramic for magnetic disks and method for manufacturing the same Expired - Lifetime US5391522A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5580363A (en) * 1993-12-09 1996-12-03 Kabushiki Kaisya Ohara Method for detecting a defect in a glass-ceramic for magnetic disks
EP0781731A1 (en) * 1995-12-28 1997-07-02 Yamamura Glass Co. Ltd. Glass composition for magnetic disk substrates and magnetic disk substrate
EP0788093A1 (en) * 1996-02-02 1997-08-06 Kabushiki Kaisha Ohara A glass-ceramic substrate for a magnetic disk
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US5788731A (en) * 1995-10-05 1998-08-04 Ngk Insulators, Ltd. Process for manufacturing a crystallized glass substrate for magnetic discs
US5837330A (en) * 1997-08-28 1998-11-17 Seagate Technology, Inc. Dual fiber optic laser texturing
US5853820A (en) * 1997-06-23 1998-12-29 Seagate Technology, Inc. Controlled laser texturing glass-ceramic substrates for magnetic recording media
US5861196A (en) * 1997-09-25 1999-01-19 Seagate Technology, Inc. Laser texturing a glass or glass-ceramic substrate
US5868953A (en) * 1994-11-16 1999-02-09 Kabushiki Kaisya Ohara Method for manufacturing a magnetic disk substrate
US5872069A (en) * 1996-12-20 1999-02-16 Ngk Insulators, Inc. Glass-ceramics for magnetic disc substrate, magnetic disc substrate and magnetic disc
WO1999008867A1 (en) * 1997-08-15 1999-02-25 Komag Incorporated Method for laser texturing a glass ceramic substrate and the resulting substrate
US5952058A (en) * 1997-01-15 1999-09-14 Seagate Technology, Inc. Laser texturing magnetic recording medium using fiber optics
US5956217A (en) * 1997-08-28 1999-09-21 Seagate Technology, Inc. Reference disk for determining glide height
US5955154A (en) * 1996-05-09 1999-09-21 Seagate Technology, Inc. Magnetic recording medium with laser textured glass or glass-ceramic substrate
US5965829A (en) * 1998-04-14 1999-10-12 Reynolds Metals Company Radiation absorbing refractory composition
US5965215A (en) * 1997-01-15 1999-10-12 Seagate Technology, Inc. Method for laser texturing a landing zone and a data zone of a magnetic recording medium
US5972816A (en) * 1996-11-14 1999-10-26 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US5981015A (en) * 1996-09-04 1999-11-09 Hoya Corporation Method for selecting a material suitable for a substrate for information recording media, material selected using this method, and magnetic disk formed using this material
US6021032A (en) * 1997-01-15 2000-02-01 Seagate Technology, Inc. Magnetic recording medium with laser textured data zone
US6020045A (en) * 1996-06-05 2000-02-01 Seagate Technology, Inc. Textured magnetic recording medium having a transition zone
KR100245281B1 (en) * 1995-10-31 2000-02-15 가지카와 히로시 A glass-ceramic substrate for a magnetic disk and a method for manufacturing the same
US6034011A (en) * 1996-09-05 2000-03-07 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic head and a method for manufacturing the same
US6063470A (en) * 1996-09-04 2000-05-16 Hoya Corporation Substrate for information recording media and magnetic disc
US6068728A (en) * 1997-08-28 2000-05-30 Seagate Technology, Inc. Laser texturing with reverse lens focusing system
US6093472A (en) * 1999-06-23 2000-07-25 Seagate Technology, Inc. Magnetic recording medium with laser textured glass or glass-ceramic substrate
US6174827B1 (en) * 1998-03-23 2001-01-16 Kabushiki Kaisha Ohara Glass-ceramic substrate for an information storage medium
US6187407B1 (en) 1997-11-14 2001-02-13 Hoya Corporation Glass substrate for magnetic recording medium and method of manufacturing the same
US6207926B1 (en) 1997-01-15 2001-03-27 Seagate Technology Llc Fiber optic laser texturing with optical probe feedback control
US6214429B1 (en) 1996-09-04 2001-04-10 Hoya Corporation Disc substrates for information recording discs and magnetic discs
US6270876B1 (en) * 1998-11-09 2001-08-07 Ngk Insulators, Ltd. Crystallized glass, substrate for magnetic disc, magnetic disc and method of producing crystallized glass
US6287663B1 (en) 1995-10-31 2001-09-11 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US6332906B1 (en) 1998-03-24 2001-12-25 California Consolidated Technology, Inc. Aluminum-silicon alloy formed from a metal powder
US6410466B1 (en) * 1999-08-10 2002-06-25 Kabushiki Kaisha Ohara Glass-ceramics for a light filter
US6413890B1 (en) * 1997-04-28 2002-07-02 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US6455451B1 (en) * 1998-12-11 2002-09-24 Jeneric/Pentron, Inc. Pressable lithium disilicate glass ceramics
US6458728B1 (en) 1999-07-06 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6458729B1 (en) 1999-07-14 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6458730B1 (en) 1999-07-14 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6468596B1 (en) 1999-07-15 2002-10-22 Seagate Technology Llc Laser-assisted in-situ fractionated lubricant and a new process for surface of magnetic recording media
US20020155216A1 (en) * 2001-04-19 2002-10-24 Reitz John Bradford Spin coated media
US6495480B1 (en) * 1998-09-11 2002-12-17 Kabushiki Kaisha Ohara Glass-ceramic substrate for an information storage medium
US6514890B1 (en) 1999-07-06 2003-02-04 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6524982B1 (en) 1999-07-06 2003-02-25 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6569791B1 (en) 1999-07-14 2003-05-27 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6569790B1 (en) 1999-07-14 2003-05-27 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6573206B1 (en) 1999-07-14 2003-06-03 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6583078B1 (en) 1999-07-14 2003-06-24 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6583077B1 (en) 1999-07-14 2003-06-24 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6593257B1 (en) 1999-07-06 2003-07-15 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6593259B1 (en) 1999-07-14 2003-07-15 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6596659B1 (en) 1999-07-14 2003-07-22 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6610620B1 (en) 1999-07-14 2003-08-26 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6624101B1 (en) 1999-07-14 2003-09-23 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6627567B1 (en) 1999-07-14 2003-09-30 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6635591B2 (en) 2000-04-03 2003-10-21 Minolta Co., Ltd. Glass composition for crystallized glass
US6642161B2 (en) 2000-04-03 2003-11-04 Minolta Co., Ltd. Glass composition for crystallized glass
US6642162B2 (en) 2000-04-03 2003-11-04 Minolta Co., Ltd. Glass composition for crystallized glass
US6645891B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
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US6645890B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6645889B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6645892B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6649549B2 (en) 2000-04-03 2003-11-18 Minolta Co., Ltd. Glass composition for crystallized glass
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US6703332B2 (en) 2000-05-16 2004-03-09 Hubei New Huanguang New Information Materials Co., Ltd. Glass-ceramic for substrate of magnetic disk having higher strength and process for the production of the same
US6715200B2 (en) 1999-02-12 2004-04-06 General Electric Company Methods for making data storage media
US20040180239A1 (en) * 2001-05-31 2004-09-16 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
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US6802894B2 (en) 1998-12-11 2004-10-12 Jeneric/Pentron Incorporated Lithium disilicate glass-ceramics
US20040241455A1 (en) * 1998-03-13 2004-12-02 Hoya Corporation Crystalized glass for information recording medium, crystallized glass substrate, and information recording medium using the crystallized glass substrate
US20050127544A1 (en) * 1998-06-12 2005-06-16 Dmitri Brodkin High-strength dental restorations
US20060040142A1 (en) * 1998-03-13 2006-02-23 Hoya Corporation Crystallized glass for information recording medium, crystallized glass substrate, and information recording medium using the crystallized glass substrate
US20180256297A1 (en) * 2017-03-08 2018-09-13 Dentsply Sirona Inc. Method to produce a monolithic form body
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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2971853A (en) * 1953-03-05 1961-02-14 Corning Glass Works Ceramic body and method of making it
US3220815A (en) * 1960-05-02 1965-11-30 English Electric Co Ltd Process of bonding glass or ceramic to metal
US3231456A (en) * 1960-02-29 1966-01-25 English Electric Co Ltd Crystalline material and method of making the same
US3238085A (en) * 1960-12-26 1966-03-01 Agency Ind Science Techn Process for manufacturing ceramiclike products from glass by microscopic crystallization
US3804608A (en) * 1971-05-24 1974-04-16 Pilkington Brothers Ltd Method for making glass ceramic materials
US3977857A (en) * 1973-10-29 1976-08-31 Westinghouse Electric Corporation Metal bonding glass-ceramic compositions having improved hardness
US4414282A (en) * 1982-04-19 1983-11-08 The United States Of America As Represented By The United States Department Of Energy Glass ceramic seals to inconel
US4480044A (en) * 1984-02-01 1984-10-30 Corning Glass Works High expansion glass-ceramic articles
US4515634A (en) * 1983-10-17 1985-05-07 Johnson & Johnson Dental Products Company Castable glass-ceramic composition useful as dental restorative
US4672152A (en) * 1985-08-05 1987-06-09 Hitachi, Ltd. Multilayer ceramic circuit board
US5219799A (en) * 1991-10-07 1993-06-15 Corning Incorporated Lithium disilicate-containing glass-ceramics some of which are self-glazing

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2971853A (en) * 1953-03-05 1961-02-14 Corning Glass Works Ceramic body and method of making it
US3231456A (en) * 1960-02-29 1966-01-25 English Electric Co Ltd Crystalline material and method of making the same
US3220815A (en) * 1960-05-02 1965-11-30 English Electric Co Ltd Process of bonding glass or ceramic to metal
US3238085A (en) * 1960-12-26 1966-03-01 Agency Ind Science Techn Process for manufacturing ceramiclike products from glass by microscopic crystallization
US3804608A (en) * 1971-05-24 1974-04-16 Pilkington Brothers Ltd Method for making glass ceramic materials
US3977857A (en) * 1973-10-29 1976-08-31 Westinghouse Electric Corporation Metal bonding glass-ceramic compositions having improved hardness
US4414282A (en) * 1982-04-19 1983-11-08 The United States Of America As Represented By The United States Department Of Energy Glass ceramic seals to inconel
US4515634A (en) * 1983-10-17 1985-05-07 Johnson & Johnson Dental Products Company Castable glass-ceramic composition useful as dental restorative
US4480044A (en) * 1984-02-01 1984-10-30 Corning Glass Works High expansion glass-ceramic articles
US4672152A (en) * 1985-08-05 1987-06-09 Hitachi, Ltd. Multilayer ceramic circuit board
US5219799A (en) * 1991-10-07 1993-06-15 Corning Incorporated Lithium disilicate-containing glass-ceramics some of which are self-glazing

Cited By (100)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5580363A (en) * 1993-12-09 1996-12-03 Kabushiki Kaisya Ohara Method for detecting a defect in a glass-ceramic for magnetic disks
US5868953A (en) * 1994-11-16 1999-02-09 Kabushiki Kaisya Ohara Method for manufacturing a magnetic disk substrate
US5788731A (en) * 1995-10-05 1998-08-04 Ngk Insulators, Ltd. Process for manufacturing a crystallized glass substrate for magnetic discs
KR100245281B1 (en) * 1995-10-31 2000-02-15 가지카와 히로시 A glass-ceramic substrate for a magnetic disk and a method for manufacturing the same
US6287663B1 (en) 1995-10-31 2001-09-11 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US6327874B1 (en) * 1995-10-31 2001-12-11 Kabushiki Kaisha Ohara Method for manufacturing a glass-ceramic substrate for a magnetic information storage medium
EP0781731A1 (en) * 1995-12-28 1997-07-02 Yamamura Glass Co. Ltd. Glass composition for magnetic disk substrates and magnetic disk substrate
US5691256A (en) * 1995-12-28 1997-11-25 Yamamura Glass Co., Ltd. Glass composition for magnetic disk substrates and magnetic disk substrate
US5874376A (en) * 1995-12-28 1999-02-23 Yamamura Glass Co., Ltd. Magnetic disk substrate
EP0788093A1 (en) * 1996-02-02 1997-08-06 Kabushiki Kaisha Ohara A glass-ceramic substrate for a magnetic disk
US5866489A (en) * 1996-02-02 1999-02-02 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic disk
US5955154A (en) * 1996-05-09 1999-09-21 Seagate Technology, Inc. Magnetic recording medium with laser textured glass or glass-ceramic substrate
EP0810586A1 (en) * 1996-05-28 1997-12-03 Kabushiki Kaisha Ohara A glass-ceramic substrate for a magnetic information storage medium and a method for manufacturing the same
US6020045A (en) * 1996-06-05 2000-02-01 Seagate Technology, Inc. Textured magnetic recording medium having a transition zone
US5981015A (en) * 1996-09-04 1999-11-09 Hoya Corporation Method for selecting a material suitable for a substrate for information recording media, material selected using this method, and magnetic disk formed using this material
US6063470A (en) * 1996-09-04 2000-05-16 Hoya Corporation Substrate for information recording media and magnetic disc
US6214429B1 (en) 1996-09-04 2001-04-10 Hoya Corporation Disc substrates for information recording discs and magnetic discs
US6034011A (en) * 1996-09-05 2000-03-07 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic head and a method for manufacturing the same
US5972816A (en) * 1996-11-14 1999-10-26 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US6124223A (en) * 1996-11-21 2000-09-26 Corning Incorporated β-quartz-based glass-ceramics
WO1998022405A1 (en) * 1996-11-21 1998-05-28 Corning Incorporated β-QUARTZ-BASED GLASS-CERAMICS
US5872069A (en) * 1996-12-20 1999-02-16 Ngk Insulators, Inc. Glass-ceramics for magnetic disc substrate, magnetic disc substrate and magnetic disc
US6207926B1 (en) 1997-01-15 2001-03-27 Seagate Technology Llc Fiber optic laser texturing with optical probe feedback control
US5965215A (en) * 1997-01-15 1999-10-12 Seagate Technology, Inc. Method for laser texturing a landing zone and a data zone of a magnetic recording medium
US5952058A (en) * 1997-01-15 1999-09-14 Seagate Technology, Inc. Laser texturing magnetic recording medium using fiber optics
US6021032A (en) * 1997-01-15 2000-02-01 Seagate Technology, Inc. Magnetic recording medium with laser textured data zone
US6303898B1 (en) 1997-01-15 2001-10-16 Seagate Technology Llc Laser texturing magnetic recording medium using fiber optics
US6204474B1 (en) 1997-01-15 2001-03-20 Seagate Technology Llc Apparatus and method for laser texturing a landing zone and a data zone of a magnetic recording medium
US6180916B1 (en) 1997-01-15 2001-01-30 Seagate Technology Llc Method of manufacturing a magnetic recording medium with a laser textured data zone
US6413890B1 (en) * 1997-04-28 2002-07-02 Kabushiki Kaisha Ohara Glass-ceramic substrate for a magnetic information storage medium
US5958545A (en) * 1997-06-23 1999-09-28 Seagate Technology, Inc. Controlled laser texturing glass-ceramic substrates for magnetic recording media
US5853820A (en) * 1997-06-23 1998-12-29 Seagate Technology, Inc. Controlled laser texturing glass-ceramic substrates for magnetic recording media
US6068891A (en) * 1997-08-15 2000-05-30 Komag, Inc. Method for laser texturing a glass ceramic substrate and the resulting substrate
WO1999008867A1 (en) * 1997-08-15 1999-02-25 Komag Incorporated Method for laser texturing a glass ceramic substrate and the resulting substrate
US6299429B1 (en) 1997-08-28 2001-10-09 Seagate Technology Llc Dual fiber optic laser texturing
US5837330A (en) * 1997-08-28 1998-11-17 Seagate Technology, Inc. Dual fiber optic laser texturing
US6068728A (en) * 1997-08-28 2000-05-30 Seagate Technology, Inc. Laser texturing with reverse lens focusing system
US5956217A (en) * 1997-08-28 1999-09-21 Seagate Technology, Inc. Reference disk for determining glide height
US5861196A (en) * 1997-09-25 1999-01-19 Seagate Technology, Inc. Laser texturing a glass or glass-ceramic substrate
US6187407B1 (en) 1997-11-14 2001-02-13 Hoya Corporation Glass substrate for magnetic recording medium and method of manufacturing the same
US20060040142A1 (en) * 1998-03-13 2006-02-23 Hoya Corporation Crystallized glass for information recording medium, crystallized glass substrate, and information recording medium using the crystallized glass substrate
US20040241455A1 (en) * 1998-03-13 2004-12-02 Hoya Corporation Crystalized glass for information recording medium, crystallized glass substrate, and information recording medium using the crystallized glass substrate
US6960399B2 (en) * 1998-03-13 2005-11-01 Hoya Corporation Crystalized glass for information recording medium, crystallized glass substrate, and information recording medium using the crystallized glass substrate
US6174827B1 (en) * 1998-03-23 2001-01-16 Kabushiki Kaisha Ohara Glass-ceramic substrate for an information storage medium
US6794043B2 (en) * 1998-03-23 2004-09-21 Kabushiki Kaisha Ohara Glass-ceramics for a light filter
US6332906B1 (en) 1998-03-24 2001-12-25 California Consolidated Technology, Inc. Aluminum-silicon alloy formed from a metal powder
US5965829A (en) * 1998-04-14 1999-10-12 Reynolds Metals Company Radiation absorbing refractory composition
US20050127544A1 (en) * 1998-06-12 2005-06-16 Dmitri Brodkin High-strength dental restorations
US6495480B1 (en) * 1998-09-11 2002-12-17 Kabushiki Kaisha Ohara Glass-ceramic substrate for an information storage medium
US6270876B1 (en) * 1998-11-09 2001-08-07 Ngk Insulators, Ltd. Crystallized glass, substrate for magnetic disc, magnetic disc and method of producing crystallized glass
US6802894B2 (en) 1998-12-11 2004-10-12 Jeneric/Pentron Incorporated Lithium disilicate glass-ceramics
US6455451B1 (en) * 1998-12-11 2002-09-24 Jeneric/Pentron, Inc. Pressable lithium disilicate glass ceramics
US20040143958A1 (en) * 1999-02-12 2004-07-29 Feist Thomas P. Methods for making data storage media and the resultant media
US6752952B2 (en) 1999-02-12 2004-06-22 General Electric Company Embossing methods
US7299535B2 (en) 1999-02-12 2007-11-27 General Electric Company Methods for making data storage media and the resultant media
US6715200B2 (en) 1999-02-12 2004-04-06 General Electric Company Methods for making data storage media
US20050233151A1 (en) * 1999-02-12 2005-10-20 Feist Thomas P Data storage media
US6093472A (en) * 1999-06-23 2000-07-25 Seagate Technology, Inc. Magnetic recording medium with laser textured glass or glass-ceramic substrate
US6514890B1 (en) 1999-07-06 2003-02-04 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6524982B1 (en) 1999-07-06 2003-02-25 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6458728B1 (en) 1999-07-06 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6593257B1 (en) 1999-07-06 2003-07-15 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6573206B1 (en) 1999-07-14 2003-06-03 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6610620B1 (en) 1999-07-14 2003-08-26 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6624101B1 (en) 1999-07-14 2003-09-23 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6627567B1 (en) 1999-07-14 2003-09-30 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6596659B1 (en) 1999-07-14 2003-07-22 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6593259B1 (en) 1999-07-14 2003-07-15 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6583077B1 (en) 1999-07-14 2003-06-24 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6583078B1 (en) 1999-07-14 2003-06-24 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6569790B1 (en) 1999-07-14 2003-05-27 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6569791B1 (en) 1999-07-14 2003-05-27 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6458730B1 (en) 1999-07-14 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6458729B1 (en) 1999-07-14 2002-10-01 Minolta Co., Ltd. Glass-ceramic composition for recording disk substrate
US6468596B1 (en) 1999-07-15 2002-10-22 Seagate Technology Llc Laser-assisted in-situ fractionated lubricant and a new process for surface of magnetic recording media
US6677259B2 (en) * 1999-08-10 2004-01-13 Kabushiki Kaisha Ohara Glass-ceramics for a light filter
US6410466B1 (en) * 1999-08-10 2002-06-25 Kabushiki Kaisha Ohara Glass-ceramics for a light filter
US6635591B2 (en) 2000-04-03 2003-10-21 Minolta Co., Ltd. Glass composition for crystallized glass
US6642161B2 (en) 2000-04-03 2003-11-04 Minolta Co., Ltd. Glass composition for crystallized glass
US6649549B2 (en) 2000-04-03 2003-11-18 Minolta Co., Ltd. Glass composition for crystallized glass
US6645890B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6645888B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6645892B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6645891B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6642162B2 (en) 2000-04-03 2003-11-04 Minolta Co., Ltd. Glass composition for crystallized glass
US6645889B2 (en) 2000-04-03 2003-11-11 Minolta Co., Ltd. Glass composition for crystallized glass
US6703332B2 (en) 2000-05-16 2004-03-09 Hubei New Huanguang New Information Materials Co., Ltd. Glass-ceramic for substrate of magnetic disk having higher strength and process for the production of the same
US20020155216A1 (en) * 2001-04-19 2002-10-24 Reitz John Bradford Spin coated media
US20100160141A1 (en) * 2001-05-31 2010-06-24 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US20060205584A1 (en) * 2001-05-31 2006-09-14 Hoya Corporation, Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US7090937B2 (en) 2001-05-31 2006-08-15 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US20090220824A1 (en) * 2001-05-31 2009-09-03 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US6818576B2 (en) 2001-05-31 2004-11-16 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US8222170B2 (en) 2001-05-31 2012-07-17 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US8697592B2 (en) 2001-05-31 2014-04-15 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US20040180239A1 (en) * 2001-05-31 2004-09-16 Hoya Corporation Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied
US20180256297A1 (en) * 2017-03-08 2018-09-13 Dentsply Sirona Inc. Method to produce a monolithic form body
US10537411B2 (en) * 2017-03-08 2020-01-21 Dentsply Sirona Inc. Method to produce a monolithic form body
CN115259672B (en) * 2022-06-24 2023-08-08 成都光明光电有限责任公司 Transparent glass ceramics and transparent glass ceramics products
CN115259672A (en) * 2022-06-24 2022-11-01 成都光明光电有限责任公司 Transparent glass ceramics and transparent glass ceramics product

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